Lunar cratering chronology: Statistical fluctuation of crater production frequency and its effect on age determination

The crater frequency is often used to determine ages of planetary surfaces. In this study, we evaluate the statistical fluctuation of the crater frequency and its effect on age determination using a Monte Carlo simulation prior to the SELENE (KAGUYA) / Terrain Camera acquiring extensive high-resolution images over the entire Moon. We found that the ages estimated between 2.5 and 3.5 Gyr tend to be too young when there are not enough craters. Age determination for Eratosthenian units is least accurate. The errors defined with 1 sigma are 0.7 Gyr for units of 100 km(2), 0.5 Gyr for units of 1000 km(2), and 0.4 Gyr for units of 2500 km(2). The maximum error exceeds 20% and is comparable with the error due to the cratering asymmetry.